title: Protein tyrosine phosphatase 1B inhibitory activities of ursane- and lupane-type triterpenes from Sorbus pohuashanensis.
abstract: Protein tyrosine phosphatase 1B (PTP1B) is a non-transmembrane protein tyrosine phosphatase, and has received much attention as a molecular target for the treatment of insulin resistance diseases because of its critical roles in negatively regulating insulin- and leptin-signaling cascades. Six ursane-type triterpenes, 3β-acetoxy-urs-12-ene-28-oic acid (1), pomolic acid-3β-acetate (2), pomolic acid (3), ursolaldehyde (4), euscaphic acid (5) and 3β-acetoxy-urs-11-en-28,13-olide (6), and a lupane-type triterpene, betulinic acid (7), from the fruits of Sorbus pohuashanensis, exhibited significant PTP1B inhibitory activity, with IC50 values ranging from 3.5 to 54.8 μM. Kinetics analyses revealed that compounds 2, 3, and 7 are non-competitive PTP1B inhibitors, and compounds 1 and 6 are mixed-type PTP1B inhibitors.
authors.affiliation: Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba, 274-8510, Japan.
authors.forename: Dongxia
authors.initials: D
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Koji
authors.initials: K
authors.lastname: Higai
authors.forename: Kazuo
authors.initials: K
authors.lastname: Koike
mesh_terms: D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000037:antagonists & inhibitors*; D031994:Sorbus / Q000737:chemistry*; D014315:Triterpenes / Q000737:chemistry* / Q000494:pharmacology*; D053978:Pentacyclic Triterpenes
chemical_list: D004791:Enzyme Inhibitors; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D014315:Triterpenes; C480546:lupane; D053978:Pentacyclic Triterpenes; C516607:PTPN1 protein, human